Suicide bombers carried out a bold attack on the world's largest oil processing facility Friday but were stopped from breaking in by guards who fired on their cars, killing the attackers.
It was the first attack on an oil facility in Saudi Arabia, and suspicion quickly fell on al-Qaida. The assault raised speculation that the militants were adopting the tactics of insurgents across the border in Iraq, where the oil industry has been repeatedly targeted.
Saudi Oil Minister Ali Naimi quickly announced that the attack "did not affect operations" and that Abqaiq operations and exports "continued to operate normally." The huge Abqaiq processing facility near the Persian Gulf prepares about two-thirds of the country's oil output for export.
Crude oil futures spiked more than $2 a barrel amid fears the industry would be targeted again.
At least two militants were killed, and Saudi-owned Al-Arabiya television reported two security guards also died. Lt. Gen. Mansour al-Turki, an Interior Ministry spokesman, could not confirm the deaths of the security guards but said two were critically wounded.
The assault began when two cars tried to drive through the gates of the outermost of three fences around the processing facility, Turki said. Guards shot at the cars, and both exploded, he said.
Al-Qaida claimed responsibility. The claim was posted on a Web site frequently used by terror groups but there was no way to check its authenticity.
Saudi Arabia has been waging a successful three-year crackdown on al-Qaida's branch in the kingdom. Security forces have killed or captured most of the branch's known top leaders, most recently in gunbattles in December.